1. Field of the Invention
The present invention relates to fast clutch mechanisms for industrial doors, and more particularly to a fast clutch mechanism for a door machine mounted at a height.
2. Background
A clutch mechanism for an industrial door is mainly used to enable a drive mechanism of a door machine to depart from the door machine when the door is subject to installation, maintenance or other urgent situations, thereby making it possible for the door to be pushed manually.
Referring to FIG. 3, in a typical industrial door, one end of a motor shaft (not shown) is connected to a worm 23. An output shaft 1 of a transmission box 14 has a worm wheel 3 engaged with the worm 23. The worm wheel 3 is restrained in an axial direction of the output shaft 1, but is rotatable with respect to the shaft in circumferential direction. In other words, the worm wheel 3 is capable of rotate relative to the output shaft 1. Idle rotation of the worm wheel 3 can result in change of the output shaft 1 between rotation status and stop status by means of a clutch sleeve 7, which is the basic principle of the clutch mechanism.
At present, there are mainly two types of clutch mechanisms for industrial doors according to the above basic principle: one employing shift fork and the other one using a spanner to uninstall the clutch mechanism. The shift fork is used to disconnect the clutch mechanism via operating one end of the shift fork; this however easily causes some failures and reduces the service life of the shift fork if the shift fork is used frequently. With respect to the other type of clutch mechanism, user needs to climb at a height to uninstall the clutch mechanism with a spanner, which takes a lot of time and energy, and is unsafe. In addition, when the door is laden, the clutch mechanism is not useful, which is inconvenient for user.
There are many sorts of clutch mechanisms applied in industry, for example, the clutch mechanism of vehicle. A clutch mechanism must be designed according to the structure of the special device which needs a clutch mechanism. Therefore, other clutch mechanisms may be unsuitable for industrial doors.